Intercommunication system



March 10,-1942.

'F.BERHLEY INTERCOMMUNICATION SYSTEM Filed Feb. 3, 1940 Patented Mar. 10, 1942 UNITED STATES PATENT oFFIcE INTERCOMBIUNICATION SYSTEM Fred Berhley, Astoria, Long Island, N. Y., assignor offorty per cent to Maxwell E. Sparrow, New

York, N. Y.

"Application February 3, 1940, Serial No. 317,149

16 Claims.

going signals from or to any remote station and any system where privacy is not 'of prime importance.

Another object of this invention is to bias all remote stations, so as to be always in a receiving position for any incoming signal. The remote 'stations to be preferably of the permanent magnet type having a voice coil suspended in a permanent magnetic eld.

A still further object of this invention is `to use the permanent magnet loud speaker, by means of a single pole single'throw switch, as either receiving or transmitting means for each remote station.

Yet a further object of this invention is to provide a remote station selector switch of the two pole single throw type, enabling an operator of any remote station to select and communicate with any other remote station in a system, without requiring the operator of the second remote station to throw or to close any selector switch, but only to displace the single pole switch at the invention relates, by adding loud speakers, switching means and interstation conductors.

Numeral I IJ designates the standard amplifier, the numeral II indicating the ampliers power supply (not shown). A capacity- I2 of suitable value is provided to eliminate stray coupling and to establish a ground path between the common conductor I9 and the B- of the power supply.

l The input transformers secondary coil I3 connects with one end to the B- of the power supl ply and with its other end to the signal grid 9 second remote in order to answer the first remote station's call.

Still another object of this invention is to provide a paging feature, whereby an operator of any remote station by means of the station selector switches may call and communicate with all other remote stations, simultaneously and thereby establish, what is known in the communication field, as a round table form of communication.

Further objects and advantages will become apparent from the following description and by reference to the accompanying drawing which shows a complete intercommunication system to which this invention relates.

A centralampliiier of the conventional type, having input and output transformers, also three remote stations are shown with each remote stations own switching means, and interstation conductors. Although three remote stations are shown to better illustrate this invention, it is understood, however, that any number of remote stations may be used in a system to which this of the amplifiers rst vacuum tube 8. The primary coil I4 connects with one end to the common conductor 'I9 and with its other end to conductor I8. Conductor I8 extends to switch positions 23, 26, and 29, respectively, of the revmote stations A, B, and C. The conductor IB is preferably of the shielded type and 'is so indicated by I8'. All ground symbols inlthe drawing refer back to the common conductor I9 and not to the power supply B. No actual connection exists between the common conductor I 9 and the power supply B except throughl capacity I2. The primary coil I5 of the output transformer connects with one end to the B-I- of the power supply and with its other end to the output or plate terminal 1 of the amplilers last or power tube 6.

One end of the secondary coil I6 of the output transformer, connects to the common conductor I9 and the other end with conductor I1.

The conductor I1 extends' to switch positions 22, 25, and 28. The single pole single throw change-over switches 2|, 24, and 21 are biased into a certain position by means of a spring as indicated by numerals 2I, 24', and 21. Voice coils 30, 3|, and 32 have one end connected to the common poles of switches 2|, 24, and 21, respectively. The remote stations selector switches are indicated bythe numerals 39, 40, and 4I for the first remote station A; 36, 31, and 38 for the second'remote station B; and 33, 34 and 35 for the third remote station C. 'I'hese selector switches are identical electrically and. may be of any convenient type so long as they have a double pole single throw action. Such switches are obtainable in many forms in the open market. Numerals 42, 43 and 44 indicate terminal strips for interstation conductors 45, 46, 41 and common I9.

Referring back to switches 39, 4U and 4Iy it can be seen that all poles are connected in parallel and also to common conductor I9. One position 39a, 40a and 4Ia, respectively, of switches 39, 40 and 4I are vjoined by a conductor 59 to the free end of voice coil 39. Conductor 41 from the second position 39h o! switch 39 joins the.

like position 38h and 33h, respectively of switches 36 and 33. Again one position 38g, 31a and 88a, respectively of switches 36, 31 and 38 are joined by a conductor 5I to voice coil 3| and one position 33a, 34a and 35a, respectively of switches 33, 34, and 35 are also joined by a conductor' 52 to voice coil 32. Conductors 45,' 4B, like conductor 41 connect together all like positions on all selector switches, thus putting a switch positions in parallel. However, voice coil 30 first position 39h of switch 39, voice coil 3| connects to the second position 31h of switch 31 and voice coil 32 connects to the second position 35h of switch 35. When referring to rst, second and third switch positions, lt is, of course, understood, that when having a plurality of seconnects to thel lector switches they would be grouped and a station number would have to be assigned to each of the switches, and therefore reference has been made to the selector switches as first, second and third in a group.

By referring to the drawing it can' be seen that any number of additional remote stations may be connected in a system of this type by adding receiving and transmitting means (loud speaker as described) with additional selector switches and additional interstation conductors and by advancing each additional remote stations voice coil to the position of the added selector switch and interstation conductor.

Should operator of remote station A, containing voice coil 30, desire to communicate with remote station C containing voice coil 32, it is only necessary for the operator of the remote station A to throw selector switch 4| into closed position, thereby connecting the voice coil 32 and voice coil 30, to the common conductor IS and thereby placing voice coils 30 and 32 across the output transformers secondary coil i6.

Displacing the pole 2l from position 22 to position 23 will place the voice coil 30 directly across the primary coil of input transformer IB. It is, of course, understood that power has been supplied to the amplifier. Any sound striking the voice coil 30 will be amplified by the amplifier l0 and reproduced by voice coil 32. After the operator of remote station A has finished his call and lets the pole of switch 2i return to its original position by means of the spring 2|', voice coil 30 will again be placed across the output transformer coil i6. The operator of remote station C containing voice coil 32 can now dispiace pole of switch 21 and thereby place the voice coil 32 across the input transformers primary I4. Any sound striking the voice coil 32 will be amplified by the amplifier I0 and will be reproduced by the remote station A in voice coil 30. After completing all communications, both operators of the remote stations A and C must let their respective switches return to their original positions. It is now clear that in any remote station the voice coils of the permanent magnet loud speakers are used as either receiving or transmitting means, by operating changeover switches 2|, 24 and 21.

Another type of intercommunication as previously mentioned may be effected by an operator of any remote station by closing all selector switches and thereby closing all return leads of all remote stations tothe common conductor I9; and by operating the change-over switch, may call all remote stations simultaneously and all remote stations may take part in the conversation by operating their respective change-over themselves to those skilled in the art and it is,

contemplated that the present invention be limited only by the claims appended hereto.

What is claimed as new and desired to besecured by Letters Patent, is:

1. In an intercommunication system, the com. bination of a central amplifier, a plurality of remotely located stations, each'of said stations having loud speaker means adapted for receiving and transmitting, and switch means at each of said stations for controlling communication circuits between stations, through their respective loud speaker means and said central amplifier,

vso

said switch means being operable to a position in which communication circuits are closed between' stations.

' 2. In an intercommunication system, the combination of a plurality of remotely located stations, a central amplifier, signal receiving and transmitting means4 at each of said stations, a first switch means at each of said stations for controlling communication circuits between stations and said central amplifier, said switch means normally occupying positions in which the communication circuits are open and operable for closing said communication circuits, anda second switch means at each of said stations and being normally positioned such that the signal receiving and transmitting means of each station after operating said iirst switch means thereby closing communication circuits between stations, are held in receiving position vacross the output of said central amplifier.

3; In an intercommunication system, the combination of a plurality of remotely located stations, a central amplifier, signal receiving and transmitting means at each of said stations, switch means including multlpole switches at each of said stations for controlling communication circuits between stations an'd said central amplifier, said -switcli means normally occupying positions in' which the communication circuits are open and operable for closing said communication circuits, and a single pole switch at each of said stations and being normally positioned such that the signal receiving and transmitting means of each station after operating said switch means thereby closing communication circuits between stations, are held in receiving position across the output of said central amplifier.

4. In an intercommunication system, the combination of a central amplifier, a plurality of stations, loud speaker receiving and transmitting means at each of said stations, means inciuding two pole single throw switches at each of said stations for controlling communication circuits between stations and said central amplifier, said switches normally occupying positions in which the communication circuits are open, and means including a single pole single throw switch at each of said stations so biased that the loud speaker receiving and transmitting means of each station are placed in receiving position across the output of said central amplier when one or more of said two pole single throw switches controlling the communication circuits are diplaced from their normal open' positions to closed positions.

5. In an intercommunication system, the combination of two or more stations, loud speaker receiving and transmitting means at each of said stations, interstation conductors and a common conductor, means including two pole single throw switches at each of said stations for con.-

K'trolling communication circuits between two or more of` said stations through said interstation conductors and said common conductor, said switches being normally open and operable\ to closed positions to connect said loud speaker reyceiving and transmitting means of two or more transmitting means at each of said stations, in-

terstation conductors and a common conductor, switch means at each of said stations for controlling communication circuits between two or more of said stations through interstation conductors and said common conductor, said switch means being normally open and operable to closed positions to connect said receiving and transmitting means of two or more of said stations to said common conductor and thereby placing said receiving and transmitting means of said two or more of said stations to receivingpositions.

7. In an intercommunicating system the combination of a common amplier having input and output circuits, two or more stations, each having transmitting and receiving means, means including multipole switches for each station at all of said stations for controlling communication circuits between stations, and a single pole switch at each of said stations so biasedas to ynormally place the receiving and. transmitting means of such station into receivingposition when one or more of said communication circuits are closed by means of their respective switches, and being operable to a second position to transf er the receiving and transmitting means of such station from the output of said common amplier to its input.

8. In an intercommunication system the combination of a common amplifier, two or more stations, each station having loud speaker receiving and transmitting means including a plurality of multipole switches, said switches normally in open position, an interstation conductor for each of said switches, and a common conductor for al1 of said switches, said interstation and common conductors being connected to said switches at like positions in all of said stations,

means including a single pole switch for each ofv said stations adapted when in normal position to connect the loud speaker receiving and transmitting means of such station to the output circuit of said amplifier to thereby close a communication circuit, when any one or more of said multipole switches are displaced from normal open to closed positions.

9. In an intercommunication system. the combination of a common amplier, two or more remote stations, each station having loud speaker means including a plurality of multipole switches so arranged as to be normally in open positions and operable to closed positions to close communication circuits of two or more stations, each station having a single pole switch so biased as loud-speaker means from the output of said'amplier to the input of mitting means.

10. In an intercommunication system, the

said amplifier as transcombination of two stations, receiving and transmitting means at each of said stations, interstation conductors and a common conductor, switch means at each of said stations for controlling the communication circuit between said two stations through said interstation conductors and said common conductor, said switch means being normally open and operable to closed position to connect the receiving and transmitting means of said two stations to said common conductor and thereby placing the receiving'and transmitting means of said two stations to receiving positions.

11. In an intercommunication system the combination of a common amplier having input and output circuits, two stations, each station `having receiving and transmitting means including a multipole switch for each station, said switches normally in open positions, an interstation conductor for each of said switches, and a common conductor for all of said switches, said interstation and common conductors being connected to said switches at like positions in both stations, a single pole switch for each of said stations adapted when in normal position to connect the receiving and transmitting means of such station to the output circuit of said amplier for receiving purpose when one of said-multipole switches is closed. y

12. In an intercommunication system the combination of a common amplifier having input and output circuits, two stations, each station having receiving and transmitting means including a multipole switch for each station, said switches normally in open positions, an interstation conductor for each of said switches, and a common conductor for all of said switches, said interstation and common conductors being connected to said switches at like positions in both stations, a single pole switch for each of said stations adapted to transfer said receiving and transmitting means to the input of said amplifier for transmitting purpose when one of said multipole switches is closed.

13. In an intercommunication system the combination of a common amplifier having input and output circuits, two stations, each station having receiving and transmitting means including a multipole switch for each station, said switches normally in open positions, an interstation conductor for each of said switches, and a common conductor for all of said switches, said interstation and Vcommon conductors being connected to said switches at like positions in both stations, a single pole switch for each of said stations adapted when in normal position to connect the receiving and transmitting means of such station to the output circuit of said amplifier for receiving and when displaced from its normal position to a second -position to transfer said receiving and transmitting means to the input circuit of said amplifier for transmitting purpose, when one of said multipole switches is closed.

14. In an intercommunication system. the combination of a plurality o! remotely located stations, a central amplier, signal receiving and transmitting means at each of said stations, a iirst switch means at each oi said stations for controlling communication circuits between stations and said central amplifier. said switch means operable for closing said communication circuits, and a second switch means at each of said stations and being positionable so that the signal receiving and transmitting means of each station after operating said first switch means thereby closing communication circuits between stations, are held in receiving position across .the output of said central amplier.

15. In an intercommunication system, the

combination of a central amplier, a plurality of stations, loud speaker receiving and transmitting means at each of said stations, switch means at each of said stations for controlling communication circuits between stations and said central ampliiier, said switch means normally occupying positions in which the communication circuits are open, and means including a single polesingle throw switch at each of said stations so biased that the loud speaker receiving and transmitting means of each station are placed in receiving position across the output o! said central ampliiler when one or more of said switch means controlling the communication circuits are displaced from their normal open positions to closed positions.

16. In an intercommunication system. the combination of a common amplifier, two or more stations, loudspeaker receiving and transmitting means at each of said stations. interstation conductors and a common conductor, switch means at each of said stations for controlling communication circuits between two or more of said stations through said amplifier said interstation conductors and said common conductor, said switch means being normally open and operable to closed positions to connect said loud speaker receiving and transmitting means oi' two or more of said statiOns to said common conductor and thereby placing the loud speaker receiving and transmitting means of said two or more of said stations to receiving positions.

FRED BERHIEY. 

